Treatment of hydrocarbons



W. F. RITTIVIAN.

TREATMENT OF HYDROCARBONS,

APPUCATION FILED FEB. 5. 1917 1,419,122 Patented June 6, 1922'.

WITNESSES PATENT OFFICE.

WALTER F. RITTMAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO SYNTHETIC HYDROCARBON COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWE.

TREATMENT OF HYDROCARBONS.

Specification of Letters Patent.

Patented June 6, 1922.

Application filed February 5, 1917. Serial No. 146,720.

To all whom it may concern:

Be it known that I, WVALTER F. RITTMAN, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in the Treatment of Hydrocarbons, of which improvement the following is a specification.

In the practice of the vapor phase cracking process described and claimed in application Serial Number 29020, filed May 18, 1915, (as fully described in Dept. of the Interior Bulletln No. 114) wherein oil in a gaseous condition is subjected to combinationsof time, temperature and pressure, dependent upon the end product desired, when reducing high boiling hydrocarbons to lower boiling hydrocarbons, it has been found that important results can be attained by effecting a partial cracking of the hydrocarbons While they are in a liquid state or condition and then discharging the partially cracked materials into a retort where substantially complete vaporization will be effected, substantially-instantaneously, the vapors heated to, orapproximately to, a cracking temperature, and then subjected to sufiicient heat to complete the cracking initiated while the material was in a liquid condition. While thus subjecting the material to progressive cracking, the reactions will occur with less violence, and it is believed with the formation of a relatively smaller percentage of undesirable end products.

The invention herein described, has for its object the cracking of petroleum hydrocarbons in two states or conditions; first, in a liquid state under pressure, which may be less than, equal to, or greater than that maintained while carrying out the second stage, which is effected by vaporizing the liquid and subjecting it while in such vaporous condition, to a temperature. of atleast 400 C. and a pressure above atmospheric and prehferably in excess of 30 lbs. per square inc In cracking the material while in a liquid condition, which is preferably carried out in a comparatively small tube, the oil is preferably subjected to a lower temperature than that maintained in effecting the final cracking after the hydrocarbons have been vaporized. As an organic reaction, the cracking of petroleum is a direct function 7 tion, showing of the time during which it is subjected to a given temperature; the results produced by applying to the material a high temperature for a short time are comparable with those produced with the application of a lower temperature for a longer time. Hence the cracking of a material in a liquid condition may be effected in a short tube if a high heat be applied thereto, or in a longer tube subjected to a lower heat, the rate of flow being the same in both cases. The final cracking after the material has been vaporized, is preferably effected in a form of apparatus permitting the vapors to flow continuously downward in a column while subjected to suitable pressure and to sufiicient heat to first raise the vapors to cracking temperature and then to a greater heat to effect the cracking.

To attain commercial conditions, it is generally desirable that oil should be treated at a rate of at least 100 gallons per hour, and as it is desirable to effect the cracking of a considerable portion of the material while in a liquid condition, the liquid should be heated to a temperature substantially higher than its boiling point, thus necessitating the application to the liquid of pressure which will generally be above that in the retort, but may be higher than that desired in effecting the final and complete cracking, and hence provision should be made for maintaining different pressures in carrying out the two operations. The pressure applied to the liquid can be controlled by proper regulation of the rate of feedof the liquid into, and its discharge from the tube, wherein it is subjected to the desired heat; and the pressure in the retort can be controlled by regulating the discharge vapors from the retort, relative to the flow of liquid from the tube into the retort. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification, Fig. 1 is a View partly in side elevation and partly in seca form of apparatus adapted for the practice of the invention described herein; Fig. 2 is a similar view of a modification of the apparatus.

In the practice of the invention, the retort 1 is arranged in a substantially vertical position within a suitably heated furnace adapted to raise the temperature of the vawith outlets into the retort. Suitable provision is made for forcing oil into the lower endof the tube, as for example, by enclosing a portion of the tube outside the retort in a drum 4 into which oil is forced by a pump 5, the oil flowing from the drum through perforations in the tube and thence up. and along the same to the outlets near its upper end.

In the operation of treating oil, the latter iscaused to flow up through the tube and while passing along the same, is subjected to the heat of the vapors contained r within the retort. By so regulating the rate.

of flow into the tube, relatlvelyto the discharge from the upper end of the tube, the

liquid may be placed under such pressure as will permit of its being heated to a crack! ing temperature without substantially vaporizing the liquid. This cracking of the liquid will be proportionate to the main cracking in the retort in a manner characteristic of my vapor phase process above referred to. The 011 being vaporized as it is discharged into the retort, thevapors heated, to or approximately to, a cracking temperature and then finally cracked a While it is preferred to employ a form of apparatus as shown in Fig. 1 and also described and claimed in applicationSerial Number 184232 filed Aug. 3, 1917, the heating-and cracking of the oil while in a liquid condition, and prior to its being fed into the retort, may be effected by any other suitable means or form of apparatus, such for example, as that shown in Fig. 2. In this construction of apparatus, the oil is fed through a coil 8 to which heat is applied by any suitable forin or construction of furnace, and then after being so heated the oil.

passes on up and is discharged into the uper end of the retort. The process of treatmg the oil in the form of apparatus shown in Fig.- 2 is identical with that shown in Fig. 1 except that the heat required for cracking the oil while in a liquid condition is obtained from a source-independent of that employed for cracking the vapors in the retort. I

As before stated, the pressure in the retort may beindependently regulated, and

hence the process and apparatus described,

for carrying it out, is adapted not onlyrfor the manufacture of liquid and products such as benzene, toluene, etc., but also for gaseous products such as ethylene, etc., where the pressure in the retort, to give the best results, should be not greater than 10 pounds absolute, as described and claimed in application Serial Number 829,169, filed April I claim herein as my invention: Y 1. The rocess herein described of'changing. the ,h1gh boilin hydrocarbons to lower boiling condensible hydrocarbons which consists in subjecting the hydrocarbons whilein a liquid condition to such temperature and pressure as to cause a substantial cracking of the liquid, vaporizing such liquid and subjecting the vapors in a vertically moving column to temperatures higher than that employed in the liquid cracking and pressure and for such a period of time as will efiect the formation of the desired low boiling condensible end product desired in substantially large quantities.

2. The process herein described of changously vaporizing substantially all the com substantially uniform mixture and subject ing such mixture in a substantially vertical unobstructed chamber to such conditions riod of time as will effect the formation of ponents of such liquid thereby effecting a j of temperature and pressure .for such a pe the desired low boilin condensible end product in "ubstantially large'quantities.

3. The process herein described of changing the hydrocarbons having high boiling points to condensible hydrocarbons having lower boiling oints which consists in passin the liquid ydrocarbons througha tube wherein it is subjected to such temperature and pressure as to cause a substantial cracking. of the liquid, discharging the. cracked hydrocarbon in a substantially ver- "tical unobstructed tube of larger diameter Y than the first, efi'ecting a completion of vaporization of substantially allthe components of the hydrocarbon discharged into. such second tube and subjecting the uniform mixture of vapors thus produced to such conditions of temperature and pressure and for'such a period of timeas will eflt'ect the formation of the desired'lower boiling con? densible end product in substantially large:

quantities' In testimony whereof, I have hereunto-set'=120;

'my hand.. 1; WALTER F. RITTMAN. 

